الفهرس 
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Abstract
Ocular C. trachomatis infections remain one of the
leading neglected infectious causes of blindness, that continue
to be of public health concern in developing countries.
Annually about one million cases reported that could be
infected by C. trachomatis according to the CDC. It is endemic
in fifty-one countries. Unfortunately, Africa is the worst
affected continent: 18 million cases of active trachoma (85% of
all cases globally) are thought to exist in 29 of the 47 countries
in WHO’s African Region.
Active trachoma is characterized by an existence of
follicles and inflammation in the upper tarsal conjunctiva. In
case of repeated infections, the upper tarsal conjunctiva may
become extremely scarred then the eyelashes transform
inwards, scratching the eyeball causing corneal opacity and
blindness. It is caused by ocular strains (A, B, Ba and C) of C.
trachomatis, which is the most prevalent in poor, rural
communities with low standards of hygiene and sanitation.
There is lack of knowledge about the extent of
Chlamydia infection as a leading cause of infectious blindness
in Egypt. Mostly the diagnosis of follicular conjunctivitis is
based on the clinical point of view with subsequent empirically
used antibiotics as a treatment which plays a role in the
development of antibiotic resistance.
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However, the follicles are not pathognomonic for
trachoma but are reasonably predictive of it when seen in
individuals living in communities where trachoma is endemic.
There are other causes of follicular conjunctivitis such as viral
infections from which the adenovirus is the most prevalent, &
toxic conjunctivitis secondary to topical drugs. So, the
observation of this clinical sign may not be specific for
Chlamydial infection.
Moreover, the worldwide increase in the prevalence of
Chlamydia infection has generated much interest in the
development of sensitive, specific, and rapid techniques for early
diagnosis which is mandatory to avoid serious complications.
Chlamydial infection was merely diagnosed by clinical
presentation and Giemsa stain for its intracytoplasmic inclusion
bodies, but patients may present with atypical symptoms. So,
its detection is based on isolation on tissue culture media which
is tedious and slow. While NAATs are the most sensitive and
specific as compared to culture. PCR is the gold standard
technique used for diagnosis C. trachomatis infection through
DNA amplification.
This study aimed to molecularly detect the presence of C.
trachomatis 16S rRNA gene in conjunctival samples which was
chosen for its specificity and its conserved nature across strains,
enabling accurate detection of the pathogen and investigate its
association with clinical features and demographic parameters
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in patients complaining of follicular conjunctivitis in an
endemic region like Egypt.
This was a cross-sectional study conducted at the
outpatient ophthalmology clinic at Ain-Shams University
Hospitals, Egypt from March to November 2023. Forty patients
with range of ages 18 to 64 years, were selected based on
clinical presentation with follicular conjunctivitis using
established criteria such as characteristic symptoms and signs
upon examination. Most of the patients (82.5%) were aged 18-
39 years old with equal distribution between 20 males and 20
females. Their median age was 26 years. Conjunctival scraping
samples were collected, and DNA extraction was performed for
amplification targeting the 16S rRNA gene of C. trachomatis
by conventional PCR in the medical microbiology laboratory at
faculty of medicine, Ain Shams University.
PCR results revealed thirty samples (75%) tested positive
for C. trachomatis, while ten samples (25%) tested negative. A
significant association between the median age and C.
trachomatis prevalence (P < 0.05) with a higher positivity rate
in young adults (76.7%) aged between 18-39 years old was
found in the present study.
In addition, our study revealed a significant gender-based
difference, with females exhibiting a higher prevalence of C.
trachomatis compared to males (66.7% versus 33.3%
respectively) (P < 0.01). Also, elucidated a highly significant
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correlation between the site of infection and PCR results (P <
0.01).
As well, our study established a significant correlation
between symptoms and PCR results, reinforcing the clinical
relevance of C. trachomatis in follicular conjunctivitis.
Symptoms such as redness founds in 39 (97.5%), foreign body
sensation in 37 (92.5%), irritation in 37 (92.5%), itching in 36
(90%), tearing in 35 (87.5%), burning sensation in 15 (37.5%),
and blurred vision in 10 (25%), were strongly associated with
positive PCR results (P < 0.01).